1. Field of the Invention
The present invention relates to a marine vessel propulsion system including operation levers arranged to be operated for controlling the respective shift states of multiple propulsion devices. The present invention also relates to a marine vessel including such a system.
2. Description of the Related Art
There has been known a marine vessel propulsion system including operation levers arranged to be operated by a marine vessel maneuvering operator to control the respective shift states of multiple propulsion devices. One example of such a propulsion device is an outboard motor.
Such a marine vessel propulsion system includes, for example, two outboard motors mounted on a hull. The two outboard motors are coupled to each other with a tie bar and arranged to have substantially the same steering angle. The marine vessel propulsion system further includes two operation levers corresponding to the two respective outboard motors. The shift state and throttle opening degree of each outboard motor can be adjusted independently by operating the corresponding operation lever. In addition, the two outboard motors are steerable through one steering mechanism.
The thus arranged marine vessel propulsion system requires a complicated operation when finely controlling the movement of the marine vessel such as when launching from and docking on shore. That is, the operator is required to finely control both the steering mechanism and the two operation levers.
The hull may include a side thruster (propulsion device for lateral movement) for easier marine vessel maneuvering when launching from and docking on shore. This, however, results in the marine vessel propulsion system having a complex structure, and is not suitable particularly for small marine vessels.
United States Patent Application Publication No. US2007/0017426A1 discloses a marine vessel propulsion system that can finely control the movement of the marine vessel easily without providing a side thruster.
This marine vessel propulsion system includes two operation levers corresponding, respectively, to two outboard motors and a cross-shaped key provided separately from the two operation levers. The shift state and throttle opening degree of each outboard motor can be adjusted independently by operating the corresponding operation lever. In addition, the two outboard motors are steerable through one steering mechanism. This marine vessel propulsion system can set a marine vessel maneuvering support mode. In the marine vessel maneuvering support mode, operating the cross-shaped key causes the steering angle, shift state, and throttle opening degree of each outboard motor to be adjusted so that the hull moves in the direction indicated by the cross-shaped key. This allows the movement of the marine vessel to be controlled finely and easily without a side thruster.